Glossary of Brewing Terms

brewing glossary - steins

Collectible German Beer Steins


As promised, here is a Brewing Glossary of common brewing terms and definitions.


ABV – alcohol by volume, expressed as a percentage

ABW – alcohol by weight, expressed as a percentage, not commonly used except in legal terms

acetic – vinegary aroma and flavor produced by acetic acid bacteria (acetobacter); common in sour beers

acetaldehyde – chemical ester which produces the off-flavor and aroma of green or rotted apples

acid – a pH value between 1 and 7

acrospire – the little shoot that develops when grain germinates during malting

adjunct – fermentable ingredient added to beer not derived from the enzymatic action during the mash. Typically rice, corn, refined or unrefined sugars or syrups.

aeration – process of adding air or oxygen to wort when pitching yeast to promote respiration

aerobic – processes that occur in the presence of oxygen

aftertaste – flavor that lingers after drinking

AHA – American Homebrewers Association; non-profit organization based in Boulder, CO dedicated to promoting the community of home brewers;

aldehyde – chemical precursor to alcohol; oxidized alcohol

ale – a major style of beer produced with “top-fermenting” ale  yeast at 60°-75°F

ale yeast – Saccharomyces cerevisiae; yeast that ferments best at 55°-75°F; also known as “top-fermenting” as it typically forms a layer of yeast on the surface during fermentation

aleurone layer – outermost layer of grain endosperm, contains enzymes which convert starches to sugars

alkaline – a pH value between 7 and 14

alpha acid – chemical compound found in the resin glands of the hop cone; source of hop bitterness

alpha acid units (AAU) – measurement of potential bitterness in hops

alpha-amylase – one of two principal diastatic enzymes that convert starches to fermentable sugars; converts starch to dextrin

American Society of Brewing Chemists (ASBC) – organization that sets brewing standards and test methods

amino acids – complex organic chemicals that are building blocks of protein

anaerobic – processes that occur in the absence of oxygen

aroma – the smell of beer associated with malt, grain, or hops

attenuation – the degree to which fermentation converts sugars to alcohol and CO2

autolysis – self-digestion and disintegration of yeast cells; can produce off flavors after primary fermentation


°Balling – one of three units used as the standard to describe the amount of available sugar in a solution

barley – cereal grain of the genus Hordeum; malted barley is the primary ingredient in beer

barm –  verb: to add or pitch yeast; noun: the foam atop a fermenting beer (kraeusen) or foam on top of a glass of beer

barrel (bbl) – standard unit in commercial brewing; a U.S. barrel is 31.5 gallons; a British barrel is 43.2 U.S. gallons

Baumé – hydrometer scale used to measure specific gravity of liquids

beer – any alcoholic beverage made by fermentation of sugars derived from grain

beerstone – hard brown scale (calcium oxalate) that deposits on brewing equipment

beta-acid – bitter acid of hops; does not contribute to bitterness due its insolubility

beta-amylase – one of two principal diastatic enzymes that convert starches to fermentable sugars; converts dextrin to fermentable sugars

beta-glucans – gums that are produced in the malting process; excess can cause “stuck” mash and prevent runoff

biotin – B-complex vitamins found in yeast

BJCP – Beer Judge Certification Program; organization that certifies beer judges and sets style guidelines for judging beer

blow-off tube – tube or hose used during vigorous fermentation to release CO2 and excess fermentation material

body – the mouth-feel of beer; thicker beers have a fuller body

bomber – a 22 oz bottle of beer

bouquet – smell of beer associated with hop character

break – phase in boiling and cooling of wort when proteins precipitate; hot break; cold break

Brettanomyces – genus of yeast used in brewing sour beers; produces acetic acid

Brussels Lace – the latticework of foam from the head on beer which is left adhering to the glass

bung – cork that seals a keg

bung hole – hole the cork goes in


calcium – mineral  ion important in brewing water chemistry

carboy – 5 or 6 1/2 gallon glass or plastic bottle with a narrow opening used as primary and secondary fermenters

caryophyllene – one of four essential hop oils; also found in basil, caraway, clove, oregano, and pepper

chill haze – protein residue that clouds beer when chilled but dissolves as beer warms

Cicerone – one who is highly educated and certified in all aspects of beer styles; similar to a wine sommelier

citronellol – monoterpene alcohol primarily biotransformed by yeast from geraniol when high levels of linalool are present

cold break – rapid precipitation of proteins that occurs when wort is rapidly cooled

conditioning – process of developing CO2 carbonation in beer bottles and kegs

cone – the part of the hops plant used in brewing; hop flower

coolship – large shallow pan used to cool wort using ambient air and collect naturally occurring yeast

copper – old term for brewpot or kettle which used to be made of copper

corn sugar – dextrose; sometimes added as adjunct to raise alcohol content and lighten color of beer; typically used in bottle conditioning


decoction – mashing technique that involves removing some of the mash to another pot, boiling it, and returning it to the mash-tun to raise temperature

dextrin – a complex sugar not normally fermentable by yeast; tasteless, adds body to beer

diacetyl – powerful flavor chemical with the aroma and flavor of butter or butterscotch; normally considered a flaw but desirable at low levels in some beer styles

diastase (diastatic) – referring to enzymes in malt that convert starches to sugars and dextrins

dimethyl sulfide (DMS) – power flavor chemical with the aroma and flavor of cooked vegetables, primarily corn or cabbage; always considered a flaw

DME – dry malt extract; concentrated wort in dry powder form

dough-in – process of mixing the crushed malt with water at the beginning of the mash

dry-hopping – adding hops directly to the fermenter at the end of fermentation to add hop aroma without adding bitterness

dunkel – German word for dark, as in color


endosperm – starchy middle of grain, source of fermentable material

enzymes – proteins that act as catalysts for chemical reactions crucial to brewing such as starch conversion and yeast metabolism

esters – aromatic compounds formed from yeast’s oxidation of alcohols; responsible for fruity aromas and flavors in beer

ethanol – type of alcohol found in beer, formed by yeast consuming sugars

ethyl acetate – most common ester in beer, at low levels it imparts a pear-like fruitiness, at higher levels it smells like nail polish or solvent

European Brewing Convention (EBC) – mostly commonly a term applied to malt color, °EBC is about twice as dark as °Lovibond/SRM

European Bitterness Unit (EBU) – equivalent of International Bittering Unit (IBU)

extract – concentrated wort; either dry malt extract (DME) or liquid/syrup malt extract (LME)


farnesene – one of four essential hop oils, very low percentage in most hop varieties, substantially higher in Noble hops

fatty acid – among secondary elements produced during fermentation, contribute much of beer’s flavor

fermentation – biochemical process by which yeast metabolizes sugars and releases CO2 and alcohol as well as many other trace elements

fermentation lock – a simple water and bubble device attached to the top of carboy to allow excess CO2 to escape and keep ambient air out

finings – clarifying agents used to facilitate the precipitation of suspended yeast, malt proteins, and polyphenols out of beer; typically gelatin, Irish Moss (carageenan) or isinglass

finishing gravity – FG; the density or concentration of sugars in the beer after fermentation; final gravity

finishing hops – aromatic hops added at the end of the boil, impart aroma and flavor but little bitterness

firkin – British cask containing 10.8 U.S. or 9 Imperial gallons

first runnings – the first few quarts of wort collected from the lauter-tun until the wort runs clear

first wort hopping – adding hops to the boil kettle as the wort is drained from the lauter-tun prior to beginning the boil

flocculation – the clumping and settling of yeast out of suspension in fermenting wort

fresh hopping – the addition of fresh, undried hops to beer during or at the end of the boil; wet hopping

fusel alcohol – group of complex alcohols that become esters under normal conditions; produced by excess amounts of yeast or letting the finished beer sit on the spent yeast too long; harsh alcohol flavor


GABF – Great American Beer Festival; the largest beer judging festival in the U.S. held annually in Denver, CO

Gambrinus – legendary European culture hero celebrated as an icon of beer, brewing, and joviality

gelatin – a fining agent

gelatinization – process of breaking down starch content of corn or other unmalted grain to make the starch accessible for conversion to sugar

geraniol – one of many hop compounds

germination – the process by which the grain begins to grow and the acrospire emerges from the hull; occurs during the malting process

glucanase – enzyme that acts on the beta-glucans of malted or unmalted grain

glucose – the most common type of sugar

gravity – specific gravity; measurement of the concentration or density of sugar in the unfermented wort or finished beer

grist – ground or milled grain ready for brewing

growler – a glass, plastic, or metal jug for transport of draft beer from the brewery to home, typically 64 oz, 1/2 gallon

gruit – a blend of herbs and spices used to flavor beer prior to hops being accepted as the most preferred bittering agent; any beer flavored or bittered without hops; a beer made with this blend

gyle – unfermented wort that is reserved for and added to finished beer for conditioning


hardness – the presence of dissolved minerals in water

helles – German word for light, as in color

Homebrew Bitterness Units (HBU)  – alternative method of determining potential hop bitterness; not related to IBU except they both measure bitterness

hops – climbing vine of the Cannabacinae family; cones/flowers give beer its bitterness and characteristic aroma

hopback – sealed container filled with hops through which the wort is filtered into the fermenter; adds hop aroma while filtering out break material

hot break – rapid coagulation of proteins and tannins, forms a brown scum on the surface of wort as boil begins

humulene – one of the chemicals that gives hops their aroma

husk – the outer covering of grain

hydrolysis – the process by which water breaks down proteins and carbohydrates

hydrometer – glass instrument used to measure the specific gravity of liquids


International Bittering Units (IBU) – accepted method of expressing hop bitterness in beer; determined by the alpha acid content and length of time in the boil

impact hops – special flavoring hops bred to produce flavor and aroma such as pine, pineapple, grapefruit, mango, and other fruits

imperial – typically indicates a stronger than usual version of a beer

infusion – most common mashing technique where grist is heated by the addition of boiling water

Irish Moss – a fining agent; carageenan; a marine algae used in the boil to promote the formation and precipitation of break material

isinglass – a fining agent made from the clear swim bladder of fish

iso-alpha acid – isomerised alpha acid; predominant source of bitterness

isomerization – chemical change during the boil that causes alpha acids and hop oils to become soluble


ju-ju – the magic that produces beer (I had to think of something for J)


kettle – brewpot; a boiling vessel; also known as a copper

kraeusen – noun: the thick foamy head on fermenting beer; verb: a priming method in which actively fermenting beer is added to finished beer


lactic acid – a tart sour acid produced by the bacteria Lactobacillus

Lactobacillus – genus of bacteria used in the production of yogurt, sauerkraut, pickles, and some beers

lactose – unfermentable sugar produced from milk; used in milk stout

lag time – the period of time between pitching yeast and the onset of fermentation

lager – from the German word for ‘to store’; beer brewed with a bottom fermenting lager yeast between 40°-55°F

lagering – the period for which lager beer is aged at near freezing temperature

lager yeast – Saccharomyces uvarum or Saccharomyces carlsbergensis; yeast which ferments best at colder temperature, 33°- 55°F; known as “bottom-fermenting” due its tendency not to form a head of yeast on the surface

Lambic – a Belgian style of beer brewed with wild yeast and souring bacteria

lautering – process in which the sweet wort is drained away from the residual spent grain

lauter-tun – vessel with a strainer bottom in which the wort is separated from the grains

lightstruck – skunky off-flavor in beer developed from exposure to light

linalool – one of many hop compounds,constitutes a tiny percentage of hop oil but, when combined with geraniol, strongly affects aroma

lipid – type of fat in animal and plant matter

liquification – process by which alpha amylase breaks up amylopectin molecules

liquor – brewers term for the hot water used in brewing

°Lovibond – method of measuring grain color; higher °Lovibond, darker color; °L

lupulin – yellow resiny substance in hops that contains all the resins and oils


magnum – a 1.5 liter bottle for beer or wine

Maillard browning – Maillard Reaction; the caramelization reaction which causes grain and other things to brown when heated

malt – barley or other grain that has been allowed to sprout, then dried and/or roasted

maltose – simple sugar that is the predominant fermentable in wort; produced from grain

mash – hot water steeping process in which starch is converted to sugar

mash-out – increasing the temperature to 170° F at the end of the mash to stop enzymatic activity

mash-tun  vessel in which mashing is done

melanoidins – strong flavor compounds produced by Maillard browning

milling – grinding or crushing of grain

modification – degree to which the starch-protein matrix breaks down during malting

mouthfeel – sensory qualities other than flavor, such as body and carbonation

myrcene – one of four primary essential hop oils. Also found in bay, thyme, and parsley


Ninkasi – Sumerian goddess of beer

nitro – any beer which is force conditioned with a nitrogen/CO2 blend rather than straight CO2

noble hops – traditional European hops which are pure wild strains that have not been crossbred, generally have low alpha acid and subtle aroma. The four noble hops, named for the regions in which they originally grew, are Hallertau, Tettnanger, Spalt, and Saaz


original gravity – OG; the density or concentration of sugars in the wort before fermentation

oxidation – chemical reaction that occurs between oxygen and various components in beer; produces a papery or cardboard like flavor and aroma


parti-gyle – brewing technique involving drawing wort off the first part of the mash and making a strong beer, then re-mashing the grain and drawing off the secondary runnings and making a weaker, or small beer

pasteurization – process of sterilizing by heat

peptidase – enzyme that breaks up small proteins in the endosperm to form amino acids

peptide – short fragment of protein

pH (potential of hydrogen) – scale used to express the level of acidity or alkalinity in a solution

phenol – chemical family responsible for spicy, smoky, clove-like and other aromas

pitch – add yeast to the fermenter

°Plato – European and American scale of gravity based on percentage of pure sugar in the wort; newer, more accurate version of the Balling scale

polyphenol – tannins that contribute to haze and staling reactions

polysaccharide – polymers of simple sugars

potential alcohol – maximum alcohol content possible from a wort if 100% attenuation is achieved

ppm – parts per million; 1 milligram per liter

precipitation – chemical process involving material coming out of solution

primary fermentation – initial rapid stage of yeast activity when maltose and other simple sugars are metabolized; primary fermenter

priming – adding a small amount of fermentable sugar before bottling or kegging to restart fermentation and condition/carbonate the beer

protein – complex organic molecules involved in enzyme activity, yeast nutrition, head retention, and colloidal stability

proteinase/protease – enzyme that breaks proteins apart into smaller, more soluble units. The process is called proteolysis.

protein rest – during mashing, a rest period at a constant temperature to facilitate proteolysis; usually between 113°- 122°F

punt – the indentation in the base of a beer or wine bottle intended to strengthen the bottle and keep sediment from being disturbed


quaff – to drink a beverage (beer) copiously and heartily


racking –  siphoning beer from one container or fermenter to another; usually to separate the beer from the trub

randall – a device filled with hops thru which beer is served, adds a fresh blast of hop aroma

real ale – ale which is conditioned or carbonated via a secondary fermentation in the bottle or keg

Reinheitsgebot – Bavarian beer purity law of 1516 decreeing that beer can only have three components: water, barley, and hops. Later amended to allow wheat and, after its discovery, yeast

respiration – aerobic and metabolic cycle which yeast performs prior to fermentation

runnings – wort that is drained from the mash during lautering


saccharification – conversion of starch to sugar through enzymatic action

Saccharomyces – scientific genus name of brewer’s yeast

Saint Arnold – Catholic patron saint of hop-pickers and Belgian brewers

Saint Augustine of Hippo – Catholic patron saint of brewers and brewing

sanitize – to reduce microbial contaminants to insignificant levels

secondary fermentation – slower phase of yeast activity during which complex sugars are metabolized; beer is typically racked to a secondary fermenter for this phase

session beer – beer that is lighter in gravity and alcohol, typically less than 4.5% ABV

set mash – during lauter and sparge, when the grain bed plugs up and no liquid flows through it; stuck mash

six-row – type of barley most often grown in the U.S. and used in production of American style lagers; so named because six rows of grain grow around a central stem; higher in diastatic enzymes

small – any beer made from the weaker second runnings from a mash after the wort is collected for a stronger beer

SMaSH – a beer brewed with only a Single Malt and a Single Hop, although there may be multiple additions of the hop

sparge – to rinse mashed grains with hot water to recover all available wort sugars

specific gravity – measurement of sugar density in wort or finished beer

SRM (Standard Reference Method) – measurement of beer color; higher number, darker beer

starch – complex carbohydrates that are converted to sugars in the mash

starch haze – suspended starch particles that cause cloudiness

steep – soaking malted grain in water at a constant temperature

stein  a German beer mug; typically very colorful and ornate but can be simple stoneware

step mash – mashing technique used controlled temperature steps

sterilize – to eliminate all forms of life by chemical or physical means

strike – addition of hot water to the crushed malt to raise temperature and begin mashing


tannins – polyphenols, complex organic materials with an astringent, tea-like flavor; comes from grain hulls and hops

terpenes – flavor chemicals in hop oils

trub – hot and cold break material, hop debris, and spent yeast yeast sediment at the bottom of fermenter

two-row – most common type of barley used in craft brewing; higher starch content; so named because two rows of grain grow on a central stem; 2-row


underlet – adding water to mash from below to allow quicker, more thorough mixing


Vinnie nail – named for Vinnie Cilurzo, Russian River Brewing; stainless steel nail used to plug hole drilled into wooden barrel to retrieve a sample of aging beer


wet-hopping – adding fresh, undried hops directly to the fermenter at the end of fermentation to add fresh hop aroma

whirlpool – device or action that separates hops and trub from wort after boiling

wine thief – glass instrument for retrieving a sample of wine or beer from a fermenter

wort – sugar-rich sweet liquid from the mash; unfermented beer

wort chiller – heat exchanger that rapidly cools wort from near boiling to pitching temperature


X-XXXX  – sometimes used to indicate strength or ABV; more X’s, stronger beer


yeast – large class of microscopic fungi that consume sugars and release alcohol, CO2, and other trace elements, several species used in brewing


zymocenosilicaphobia – Fear of an empty beer glass

zymurgy – the science of brewing and fermentation

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